Engineering

[omenyilameck]

a test of a driver's perception reaction time is being conducted on a special testing track with wet pavement and a driving speed of 50 kph. when the driver is sober, a stop can be made just in time to avoid hitting an object that is visible 40 m. ahead. after a few drinks of san miguel beer, under exactly the same condition, the driver fails to stop in time and strikes the object at a speed of 30 kph. determine the driver's perception-reaction time after he was drinking. assume coefficient of friction is 0.60.

[ToraToraTora]

42

[TheChair]

2 bananas and a peach

[bhg481]

You can calculate the acceleration in the first case using the standard formula involving initial speed, final speed, acceleration and distance.
Substitute for acceleration in standard formula involving initial speed, final speed, acceleration and time to calculate the time taken to stop.
Use same acceleration value to calculate time to slow from 50 kph to 30 kph.
I can't see any need to use the coefficient of friction other than to be aware that it puts an upper limit on the acceleration.

[douglas9401]

'A few drinks' is a bit vague when other factors are absolute.

Is this a thinly disguised ad for San Miguel?

[Togo]

If the driver is on the pavement at 50kph he, is on something stronger than gnats ***. What I want to know is what was the "object" was on that enabled him/her to run away at 20kph or where I can get a disability cart with that sort of performance. Of course a slippage coefficient of .6 indicates that the pavement has been cleared of discarded face masks and chewing gum, and other factors indicate that the driver's reaction time and perception has less to do with the collision than his/her intent. Please call back when I am out and leave a more detailed and advanced level conundrum for our experts.

[Togo]

I hope that there is no religious involvement in this "question".